With summer beach season here, avoiding skin cancer—the most common form of the disease, afflicting three million Americans annually—just got more complicated. Everyone knows that sunscreen helps reduce the risk of developing skin cancer. But a recent US Food and Drug Administration (FDA) study has found that active ingredients in sunscreen can ooze into your bloodstream.

The FDA says 2 of 14 ingredients are safe when absorbed into the blood, but copped to a we-don’t-know about the other dozen, requesting more safety data from manufacturers. So should you slather on the ’screen, and if so, which are the safest brands to use?

We asked Debjani Sahni, the School of Medicine G. Robert Baler endowed professor of dermatology and director of the Boston Medical Center Cutaneous Oncology Program. She answered—while reminding people “that sun protection is a multipronged approach” and sunscreen is just one aspect. Protective steps include “seeking shade, wearing protective clothing, including sunglasses, and generously applying a broad-spectrum sunscreen that is water-resistant and SPF 30 or more on exposed skin.”

Q&A

BU Today: In light of the FDA study, should people still use sunscreen?

Sahni: In short, yes. We should take into account the available scientific data so far. We know that skin cancer is the most common type of cancer in the United States, and one in five Americans will be diagnosed with skin cancer in their lifetime. We also know that damage to the skin from UV radiation is the number one cause of skin cancer. The use of sunscreen has been scientifically proven in humans to reduce the risk of developing skin cancer and precancerous lesions.

The recent study addresses an important issue. However, the results of the study do not confirm that this absorption actually leads to any significant effect on a person’s health. To answer this question, more studies are needed, which the FDA plans to undertake. Sunscreens have been around for decades, and there are no reports to date of any negative internal effects on humans. For now, taking all the information into account, the advice is to continue using sunscreen. In fact, this is also the recommendation by the authors of the FDA study.

What are the ingredients of concern in sunscreen, and what are the possible harms they can do?

The four ingredients tested in the study were oxybenzone, avobenzone, octocrylene, and ecamsule. Oxybenzone can penetrate the skin and potentially interfere with hormone levels. Some of this concern comes from earlier animal studies, although a study in 2004 did not show significant hormone disruption in humans. Initial research on oxybenzone also points to a potential environmental issue, in that it may be partially responsible for damaging coral reefs. Regarding the other three ingredients, more research is needed to know the true impact, if any, on the health of humans.

Can people purchase sunscreens that don’t contain the potentially risky ingredients?

There are two types of sunscreens: physical and chemical. Physical sunscreens work by reflecting or blocking the sun’s rays. They contain zinc oxide and/or titanium dioxide. These ingredients have been determined as GRASE—Generally Regarded As Safe and Effective—by the FDA and do not require further testing.

The other ingredients available in sunscreens are present in chemical sunscreens. These work by absorbing the sun’s rays and converting them into heat. Presently there is insufficient data to be able to make a positive GRASE determination on these ingredients in chemical sunscreens. Hence the ongoing tests. You can know the type of sunscreen you are buying by looking at the list of ingredients on the back of the sunscreen bottle.

What brands would you recommend?

As they are regulated by the FDA, what is more important than the actual brand is the regulatory label on the bottle. Make sure the sunscreen is labeled as “broad spectrum.” This implies the sunscreen provides proportional protection against both UVA and UVB rays, as they are both important in causing skin cancer. Also, ensure that the sunscreen has adequate SPF (Sun Protection Factor). Studies show that an SPF 15 can reduce the risk of skin cancer developing. However, the American Academy of Dermatology encourages people to use sunscreen with an SPF of 30 or more, given that people typically do not apply adequate amounts of sunscreen. This is my recommendation also.

How many cases of skin cancer do you typically treat in a year?

I typically see and treat over 2,000 skin cancer patients a year and diagnose around 350 new skin cancers annually.

—Rich Barlow